The present subject matter relates generally to implantable medical devices, and particularly, but not by way of limitation, to an apparatus and method for introducing a lead into a connector block of a pulse generator.
Implantable pulse generators are integrated, highly sophisticated systems comprising a lead and a pulse generator. The lead is the only link between the electronics in the pulse generator and the heart. Thus, the lead plays a critical role of delivering the output pulses from the pulse generator to the myocardium and transferring the intracardiac electrogram from the myocardium to the sensing circuits of the pulse generator.
The main components of the cardiac lead includes one or more electrodes, one or more lead conductors, lead insulation, and a lead connector. Generally, the one or more electrodes are each individually coupled to the one or more lead conductors, which in turn are coupled to the lead connector. The lead insulation electrically and physically isolates the lead conductors and provides a surface on which the one or more electrodes reside.
The lead conductor of the cardiac lead is typically a coil of wire that conducts electric current from the pulse generator to the electrode. The conductor is also responsible for conducting the sensed cardiac signals from the electrodes to the sensing amplifier of the pulse generator. One common conductor design is of a multifilar coil arrangement which is helically coiled to create an empty core. The empty core allows for the passage of a stainless steel stylet which aids in the implanting of the cardiac lead.
There are two basic approaches for the implantation of an implantable pulse generator. The first is the epicardial approach and the second is the transvenous approach. The epicardial approach calls for direct application of electrodes on the heart. The transvenous approach calls for inserting the cardiac lead into the patient""s heart through the cardiac veins. Today, approximately 95% of all pacemaker implantations are performed transvenously.
Once the cardiac lead has been implanted into the patient""s heart the lead connector is coupled to the pulse generator. Lead connectors typically have low-profile, in-line connector pins which are inserted into a socket located on the pulse generator. The lead connector also has sealing rings which prevent fluids from entering the socket of the pulse generator once the lead connector has been seated in the pulse generator. Once seated in the socket, the in-line connector pins make contact with terminals which couple the one or more electrodes on the surface of the cardiac lead with the electronics within the pulse generator.
Possible problems can arise when the lead connector is inserted into the socket of the implantable pulse generator. For example, it is possible to bend the cardiac lead at an acute angle as the lead connector is being inserted into the socket. When this occurs, there is the possibility of over-flexing the lead conductor within the cardiac lead causing the conductor to stress and/or break. A damaged lead conductor could then lead to intermittent sensing and/or pacing by the pulse generator, which in turn may endanger the patient""s health. This problem is due, in part, to the flexibility of the lead and the seal drag created in the socket as the cardiac lead is inserted into the pulse generator with the required insertion force.
Recommendations for inserting lead connectors into a pulse generator include inserting the lead connector straight into the pulse generator, being careful to avoid bending or pinching the cardiac lead as it is being inserted into the socket of the pulse generator. Additionally, it is recommended to avoid tight bends in the lead terminal during the insertion procedure and when placing the pulse generator into the patient. Even with these recommendations, given the time critical nature of implanting a pulse generator there is still the danger of damaging the cardiac lead while it is being inserted into the pulse generator. Therefore, a need exists for reducing the danger of damaging the cardiac lead as it is being inserted into an implantable pulse generator.
The present subject matter provides for a reduced likelihood of damage to a flexible lead as the lead is inserted into a device. In one embodiment, the present subject matter provides for an apparatus and method for supporting a cardiac lead as the lead is inserted into the implantable pulse generator. The apparatus and method of the present subject matter provide a sleeve, or collar, disposed at least partially around the body of the cardiac lead. The sleeve provides a surface with which to hold the cardiac lead and also provides support to the lead to prevent bending or pinching the cardiac lead as it is being inserted into the socket of the pulse generator.
In one embodiment, the apparatus comprises the sleeve. The sleeve is an elongate body having a peripheral surface, a first end and a second end. The sleeve also includes an opening extending from the first end to the second end, where the opening in the sleeve at least partially surrounds and supports (e.g., prevents lateral deflections of the lead) at least a portion of the cardiac lead. In one embodiment, the opening is eccentric or centric relative the longitudinal axis of the sleeve. The sleeve also includes a first slit extending from the peripheral surface to the opening and from the first end to the second end, where the cardiac lead is passed through the first slit to remove the sleeve from the cardiac lead.
Cardiac leads typically include a lead connector at the proximal end of the lead. When coupling the cardiac lead to the implantable pulse generator, the lead connector is inserted into the connector block of the implantable pulse generator. In one embodiment, the sleeve of the present subject matter is positioned distal to the lead connector to allow for the lead connector. In one embodiment, the sleeve is positioned on the lead so that the lead connector can be fully seated within the connector block while the sleeve provides support to the cardiac lead.
In an additional embodiment, the sleeve includes a releasable closure strip which joins the sleeve along the first slit. In one embodiment, when the releasable closure strip is removed, the sleeve self-opens (e.g., sleeve returns to a relaxed state) to form a pass through opening in the sleeve which allows the cardiac lead to pass through the pass through opening.
In an alternative embodiment, the sleeve includes a second slit extending from the peripheral surface to the opening and from the first end to the second end. Having a first and second slit divides the sleeve into a first and second housing portion. A hinge is provided along the second slit to join the first and second housing portions and provides a point around which the two housing portions pivot once the releasable strip is removed from the first slit.